None of these things seem inherently interesting or fun. It feels like a designer's mechanic rather than a player's mechanic. Cleverness for cleverness' sake that leads to worse gameplay.
Not to mention, most of what you could be done with creatures just fine with a little bit of legwork.
I don't thing this makes for interesting gameplay, but even we assume it does, this can still be done with creatures. You could give the creatures subtypes or have the spells care about something all of the creatures have in common, like "Return target creature card with power 1 or greater from your graveyard to your hand."
Which is the same as a creature.
Again, this isn't terribly interesting from the player's perspective, And it could still be done with creatures by giving them a
Doran/
Assault Formation type ability.
Colors that aren't red generally shouldn't be dealing damage, even to noncreature permanents. And again, this space can still be explored on creatures just by caring about a specific attribute, as seen on cards like
Crux of Fate and
Whipflare.
This isn't terribly different from effects that buff your creatures' toughness.
If it didn't matter at all, why would it even be on the card? A "vanilla" Endurance/Withstand artifact takes up extra mind space while not actually doing anything of significance that's different than a run-of-the-mill wall.